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4 ULTS IN HYBRIDIZATION OF BEARDED IRIS — MUC CES 
di: MANY ANT AT | Ÿ Ars 
foresee, but with the assurance that, with perseverance, you will 
find there more than you sought. 
The particular aims, in which I was chiefly interested, were to 
_ obtain a crimson Iris and a plicata with a golden yellow ground. 
I had the desire to break new ground and such varieties were 
entirely unrepresented in bearded Iris at that time. All other aims 
_ which I had in mind were more of the nature of improving varieties 
ee ea 
that already existed. Of the more general aims, which every cons- 
cientious breeder must attend to in seeking to improve flowers, 
‘special consideration was given to increasing the substance and 
broadening the segments. 
Neither of the two special aims, — the crimson Iris and the yellow 
ground plicata, — has yet been attained, but much may often be 
learnt from failure. The work done will perhaps not be entirely 
wasted, and may help to pave the way, if the experience gained is 
. shared with these who may take up the quest, and some account of my 
_ attempts may be of interest and save others from much barren labour. 
_ The advances made towards a crimson Iris are very slight and seem 
to show that, if it is possible, the right direction to work has not 
yet been found. It may be that it is unattainable, though I do not 
think so. But there is one consideration why it may be, at any 
rate, specially difficult. Willstatter (quoted in The Anthocyanin 
_ Pigments of Flowers, by Miss M. Wheldale) expresses the opinion 
that ‘ variation in flower-colour largely depends on the presence 
_ of other substances, acids, alkalies, salts. etc., in the cell-sap ”. The 
_ blue type of Centaurea, for instance, contains the alkaline (potas- 
sium) salt of the pigment of the purple variety, To put it more 
fully : — In Centaurea flowers, there are three modifications of 
one anthocyanin pigment : a purple pigment, cyanin, which is it- 
self free acid; a blue pigment, which is the potassium salt of 
the purple...; and a red pigment, which is the oxonium salt of 
the purple with some organic acid ”. 
The pigment forming processes are not the same in all flowers 
and it does not follow that they are the same in Iris as in Centaurea, 
but it is significant that red is associated with acid, and blue with 
alkaline substances. As is well known, bearded Iris grow best in 
a calcareous soil, and become unhealthy if the soil is at all defi- 
a ee TE TJ 
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coh 7 
cient in lime. That is, they thrive in comparatively alkaline 
medium and resent an acid condition. It does not follow that they 
would therefore be unable to elaborate the necessary acid substances 
for the production of a red pigment, for there are many plants which 
thrive in a calcareous soil which have red flowers, but it might 
well be that it would be less easy and less natural to develop 
the acid than the alkaline type of pigments. 
